CAT2300
Current Monitor for 0.9 V -
1.5 V Bus
Description
CAT2300 is a controller for MOSFET current monitoring in
high-side switch applications.
CAT2300 provides current mirroring and ON/OFF control for
MOSFETs. Exact control and matching of the Sense output of the
MOSFET with the Kelvin voltage insures accurate current monitoring
over a couple of decades of current.
CAT2300 is the single chip alternative to discrete circuits for
monitoring and controlling 0.9 V − 1.5 V power busses. When teamed
with a MOSFET, CAT2300 will track currents up to 25 A and resolve
currents below 100 mA.
CAT2300 provides logic level ON/OFF control of the power
MOSFET and its own internal circuitry, reducing power consumption
to virtually zero milliwatts.
CAT2300 operates over the full industrial temperature range of
−40°C to +85°C.
Features
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1
TDFN8
VP2 SUFFIX
CASE 511AK
PIN CONFIGURATION
Sense
KS
Kelvin
Gate
(Top View)
1
I
MEAS
EN
V
DD
GND
•
Precision Current Measurement of 0.9 V − 1.5 V Power Supply Rails
•
ON/OFF Power FET Control with Soft−start
•
Sense Current Mirroring to 70 mA
•
•
•
•
(equal to 25 A flowing in the power bus)
User Adjustable Current to Voltage Conversion Ratio
150
mV
Typical Matching between Kelvin and Sense Leads
Less than 1
mA
Current Consumption in Shutdown Mode
This Device is Pb−Free, Halogen Free/BFR Free and RoHS
Compliant
MARKING DIAGRAM
F3T
LAA
YM
G
F3T
L
AA
Y
M
G
= Specific Device Code
= Assembly Location Code
= Assembly Lot Number
=
(Last Two Digits)
= Production Year (Last Digit)
= Production Month (1−9, O, N, D)
= Pb−Free Microdot
Typical Applications
•
Portable Computers
•
Backplane Bus Control
•
Power Distribution
Power Bus
SENSEFET
System
Load
ORDERING INFORMATION
Device
CAT2300
Package
TDFN
Marking
F3T
Shipping
†
3,000 / Tape &
Reel
Enable
I
MEASURE
CAT2300
Figure 1. System Application
†For information on tape and reel specifications,
including part orientation and tape sizes, please
refer to our Tape and Reel Packaging Specification
Brochure, BRD8011/D.
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 5 of this data sheet.
©
Semiconductor Components Industries, LLC, 2012
1
April, 2017 − Rev. 4
Publication Order Number:
CAT2300/D
CAT2300
Gate Kelvin KS
Sense
VREG
1
V
DD
0
EN
250
mA
+
−
I
MEAS
GND
Figure 2. Simplified Block Diagram
Table 1. PIN FUNCTION DESCRIPTION
Pin No.
1
2
3
4
5
6
7
8
PAD
Pin Name
Sense
KS
Kelvin
Gate
GND
V
DD
EN
I
MEAS
Function
Connects to Sense pin of MOSFET and directs sensed current to IMEAS output.
Kelvin Sense; a Kelvin connection for the current mirror control amplifier. This connection must be made
directly to Sense on the MOSFET package. Do not share any trace length with CAT2300’s Sense lead.
Connects to Kelvin pin of the MOSFET. Serves as the reference point for Sense lead biasing.
Connects to Gate of the MOSFET and controls MOSFET operation.
Electrical ground for IC.
External voltage supply for driving the gate of the MOSFET and power supply for CAT2300 internal
circuitry via an internal voltage regulator.
Enable: High true logic input. Turns ON MOSFET and CAT2300’s internal circuitry. A logic LOW on EN
grounds Gate, shutting off the MOSFET and shuts down the internal current source and mirroring circuitry.
Sensed current output. A resistor between I
MEAS
and ground develops a voltage proportional to the
current flowing through the MOSFET.
Backside paddle is internally connected to GND. This pad may be left floating but if connected with PCB it
must be to the ground plane of circuitry which is also grounded.
Table 2. ABSOLUTE MAXIMUM RATINGS
(Note 1)
Parameter
V
DD
Gate
V
K
, EN, Sense, KS, Kelvin, I
MEAS
Junction Temperature
Symbol
V
DD
Value
6.5
±15
6.5
150
Unit
V
mA
V
°C
Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality
should not be assumed, damage may occur and reliability may be affected.
1. Guaranteed by design.
Table 3. RECOMMENDED OPERATING CONDITIONS
Parameter
V
K
V
DD
Maximum Junction Temperature
Ambient Temperature Range
Symbol
V
K
V
DD
T
JUNCTION
T
AMBIENT
Value
0.9 to 1.5
5
125
−40 to +85
Unit
V
V
°C
°C
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CAT2300
Table 4. PACKAGE THERMAL PERFORMANCE
Package
TDFN−8
Symbol
q
JA
q
JC
q
JA
q
JC
Test Conditions
1 oz Copper Thickness, 100 mm
2
Min
Typ
160
35
160
25
Max
Unit
°C/W
SOIC−8
1 oz Copper Thickness, 100 mm
2
°C/W
Table 5. DC ELECTRICAL CHARACTERISTICS
(V
K
= 0.9 – 1.5 V; V
DD
= +5 V; T
AMBIENT
= −40°C to +85°C, T
JUNCTION
= −40°C to +125°C, unless otherwise specified.)
Limits
Parameter
Kelvin voltage
Gate Drive input voltage
Supply Current on V
DD
pin
Symbol
V
K
V
DD
I
VDD
EN = logic 0
EN = logic 1
Gate drive Sourcing
Gate drive Sinking
Offset Voltage
Input Bias Current;
Kelvin and KS inputs
Power Supply Rejection Ratio
I
MEAS
output current
Output voltage of I
MEAS
amplifier
LOGIC
Low level input voltage
High level input voltage
Hysteresis
Low level input current
High level input current
I
IL
I
IH
EN, V
DD
= 0 V or 5.5 V
EN, V
DD
= 0 V or 5.5 V
V
IL
V
IH
EN
EN
0.9
1.4
1.1
1.65
0.55
2
2
1.26
1.9
V
V
V
mA
mA
V
OS
I
K
PSRR
I
MEAS
V
O_IM
0
0
I
GATE
V
GATE
= V
DD
– 1 V
V
GATE
= 0.6 V
V
OS
= V
KELVIN
− V
SENSE
V
K
= 0.9 V to 1.5 V
65
−235
7
77
−280
9.6
±150
100
70
70
V
K
– 0.1
Test Conditions
Min
0.9
4.5
Typ
Max
1.5
5.5
1
100
−330
13
±300
150
Units
V
V
mA
mA
mA
mA
mV
nA
db
mA
V
Table 6. AC OPERATING CHARACTERISTICS
(V
K
= 0.9 V – 1.5 V; V
DD
= 5 V; T
AMBIENT
= −40°C to +85°C, T
JUNCTION
= −40°C to +125°C, unless otherwise specified.)
Limits
Parameter
I
MEAS
output rise time
I
MEAS
output fall time
I
MEAS
Settling time
Symbol
t
R
t
F
t
S
Test Conditions
20
W,
100 pF, V
K
= 1.5 V
I
SENSE
: 2 mA – 70 mA
EN = Logic 0³1, I
SENSE
= 1 mA
EN = Logic 0³1, I
SENSE
= 70 mA
Min
Typ
38
33
30
50
Max
Units
ms
ms
ms
ms
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CAT2300
TYPICAL PERFORMANCE CHARACTERISTICS
I
Bus
V
MEAS
50
ms
/ div
Figure 3. Load Step: 1 A – 10 A
PIN DESCRIPTION
Sense
Sense connects directly to the MOSFET’s Sense pin and
directs the sensed current to the I
MEAS
output. Sense is
controlled by an amplifier with a FET follower stage to
maintain Sense at exactly the Kelvin voltage, thus insuring
accuracy of the MOSFET’s mirror current.
KS
KS = Kelvin Sense; a Kelvin connection for the mirroring
amplifier. Current measurement accuracy is dependent upon
the voltage match between the MOSFET’s Sense and Kelvin
leads. To minimize voltage losses in the PCB trace between
CAT2300 and the MOSFET, a Kelvin connection for the
control amplifier is provided.
KS must be a dedicated
connection, shared by no other circuitry,
and tied
directly
to the Sense pin on of the MOSFET.
Careful layout is critical in achieving full MOSFET
perfomance. PCB trace resistance can no longer be ignored
as it can be in typical low current circuit designs. Microvolt
offsets (mV) produce meaningful errors in current ratio
tracking. A few milliohms of trace resistance carrying a few
milliamps of current produces microvolts of potential
difference between CAT2300 and the MOSFET. To
circumvent this error CAT2300 provides a Kelvin lead (KS)
for monitoring the MOSFET’s Sense pin. Under no
circumstances should the KS connection share any portion
of the current path between the sense pins of CAT2300 and
the MOSFET. Doing so will degrade measurement accuracy.
Kelvin
Kelvin connects directly to the MOSFET’s Kelvin pin and
acts the reference voltage for CAT2300’s mirroring circuit.
It too must be a dedicated connection, shared by no other
circuitry.
Gate
MOSFET
MOSFET
MOSFET
Gate connects to the MOSFET’s Gate pin and controls the
MOSFET’s operation. Gate is controlled by EN: a logic 1
turns the MOSFET ON, a logic 0 turns it OFF. When ON,
voltage is applied to the MOSFET’s gate via a current source
inside CAT2300.
By controlling the gate drive current a controlled turn-ON
is achieved. Faster turn-on times can be done by adding a
supplemental current source to augment the internal current
source. Placing a resistor between V
DD
and Gate will
provide extra current and boost turn-on speeds.
For a softer turn-on characteristic, add capacitance
between the MOSFET’s Gate and Source pins;
approximately 1 nF for every ms of increased delay.
When switching OFF the MOSFET, Gate provides a
strong pull-down, 7.5 mA typical, so the MOSFET will be
switched off quickly.
Figure 4. Current Sense
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CAT2300
V
DD
EN
V
DD
provides gate drive for the MOSFET and power for
CAT2300’s internal circuitry and must be +5 V.
I
MEAS
I
MEAS
is the mirror current output. Placing a resistor
between I
MEAS
and ground produces a voltage proportional
to I
BUS
. The maximum voltage producible at IMEAS is the
Kelvin voltage (V
K
) – 0.1 V. This sets a limitation on the
maximum value of R
MEAS
.
R
MEAS
+
V
K
*
0.1 V
+
CSR
I
SENSE
V
K
*
0.1 V
I
bus
Enable is a high true logic input controlling the
MOSFET’s ON/OFF state. A logic high on EN turns the
switch ON; a logic low turns it OFF.
Bus turn-ON time is controlled by the FET’s input gate
capacitance and the drive current applied to the gate.
To minimize power consumption EN disables the internal
gate drive current source and current mirroring circuitry
whenever the MOSFET is OFF.
where:
CSR = Current Sensing Ratio taken from the MOSFET data
sheet.
I
bus
= Max current through the MOSFET.
NTMF4834NS
Kelvin
V
IN
Drain
I
bus
Gate
Gate
Kelvin KS
Source
Sense
V
OUT
I
Sense
Sense
VREG
1
V
DD
0
EN
V
MEAS
250
mA
+
−
I
MEAS
CAT2300
GND
Figure 5. Typical Application
ORDERING INFORMATION
Part Number
CAT2300VP2−GT3
2.
3.
4.
5.
Temperature Range
−40°C to +85°C
Package
TDFN
Quantity per Reel
(Note 5)
3,000
Package Marking
F3T
All packages are RoHS−compliant (Lead−free, Halogen−free).
The standard lead finish is NiPdAu pre−plated (PPF).
For additional package and temperature options, please contact your nearest ON Semiconductor Sales office.
For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging
Specifications Brochure, BRD8011/D.
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